JP2528659B2 - Measuring instrument and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to metrology, and in particular to an instrument capable of measuring properties of a workpiece such as surface radius, shape or surface texture.

When manufacturing precision components, it is desirable to check their surfaces to ensure that they meet the specifications required by the end user. Such checks are performed by metrology tools, which are delicate and fairly sensitive and have traditionally been placed in special measuring rooms located away from the production line to protect them from accidental damage. It was As a result, it was necessary to carry the components from the production line to the measurement room for checking and then back to the production line for further processing. This is time consuming and therefore costly, and therefore specifically improves the efficiency of the measurement operation when the same component is manufactured in large quantities and everything should preferably be checked. There is a need. Traditionally, the development of metrology tools
We focused on increasing its accuracy and operating speed by improving the routines performed in the measuring operation, which are computer controlled in modern instruments. This approach to increasing speed naturally only reduced the time taken for the measurement operation itself.

The purpose of the present invention is to dramatically increase the efficiency with which many identical components can be checked.

In one aspect, the invention provides a sensor for checking the surface of a workpiece in a retracted position placed within a protective housing, and a motion protruding from the housing to engage the surface of the workpiece to be checked. Provide a metrology instrument that is arranged to move to and from a position.

In another aspect, the invention is operable to repeatedly move a sensor along or around a predetermined path to make measurements on the same workpiece in series. A metrology instrument having a drive means. In a preferred embodiment, the mechanism is set to any one of a plurality of states, each providing a respective different said predetermined path so that the instrument can be used to check different components. Means for doing so are provided.

A further aspect of the present invention is operable to perform a predetermined measurement cycle in response to actuation of a single start button, thereby allowing the cycle to be repeated on similar workpieces in series. Is to provide an instrument.

In another aspect, the invention provides a setup instruction and / or
Or a first means for entering data and the first means for repeatedly starting a predetermined measurement cycle.
And a second means separate from the means of. The second means is preferably a single button. First
The means is preferably a terminal device removable from the instrument.

In a further aspect, the invention provides a method for making a number of identical workpieces on which metrology operations are performed on at least a majority of the manufactured workpieces.

The invention will be further described by way of example with reference to the accompanying drawings.

Referring to FIG. 1, the device includes a main unit 500, a terminal device 502 and a printer 504.

The unit 500 comprises a housing 506, on top of which a workpiece support structure 508 is mounted and a measuring tool 510. The structure 508 and tool 510 are
Described in more detail. The tool 510 is placed in a partition 512 defined between a front wall 514 of the housing 506, a pair of side bulkheads 516 and a lateral bulkhead 518. The fan 520, which is placed on the partition 512, moves the housing 506 from below to the bottom wall 52
Atmosphere is drawn into the partition 512 through a hole in 2 and this atmosphere passes over the tool 510 and its edge is on the upper edge of the partition 516 which is spaced below the upper part 6 of the housing 506. Will be sent to. The electrical and electronic circuitry (not shown in FIG. 1) has a partition 5 towards the rear of the housing 506.
Placed at 24. The atmosphere passing through the partition 512 by the action of the fan 520 maintains the tools 510 at ambient temperature and prevents them from being heated by the warm atmosphere from the partition 524. This arrangement has been found to be particularly advantageous in stabilizing the accuracy of the instrument, since the atmospheric transfer described has been found to quickly stabilize the instrument. In this regard, changes in the temperature of the tool 510 can cause its thermal expansion or contraction, which in turn can result in inaccurate measurements.

Front facing digital displays 526 and 528 are mounted towards the rear of housing 506. The information display plate 530 displays the display 526 to show the importance of some numeric code appearing on the display 526.
Positioned in front of the. Switches 532, 534 and 536
Power on and off the printer 50 respectively
4 is provided for activating it to print the result of the measuring operation and for starting the measuring operation.

The terminal device 502 includes a keyboard 538 and a liquid crystal display 540 capable of displaying graphics and text. The terminal device 502 and the printer 504 are each connected to the unit 500 by a disconnectable data cable 542.

The following more detailed description of the structure and operation of the preferred embodiment of the present invention is made assuming that the instrument is to be used to measure the concave toroidal surface of a race.

Referring to FIG. 2, the race 2 has a concave toroidal surface 4 whose radius and shape are to be checked by an instrument according to a preferred embodiment of the present invention, and which is manufactured by a mass production method and all of which are One of the many such races that should be checked
Individual. The metrology tool to perform this check is
It is configured so that it can be positioned on a work table (not shown) directly adjacent to the production line without substantial risk of damage, and has a measuring cycle of high speed and high speed which is particularly suitable for the particular race 2 to be checked. Deployed to perform at high repetition rates.

The structure 508 includes a jig (not shown in FIG. 2) on which the race 2 is supported. Stylus 8 (only its tip is second
(Visible in the figure) is 1 in each measurement cycle, around the closed path indicated by the dashed line 10 in FIG.
Arranged to move only once. When the instrument is not in motion, the stylus 8 is placed in the position 12 where it retracts into the housing. At this time, the holes 14 provided in the upper portion 6
Is covered by the shutter 16 and thus the stylus is sufficiently safe against accidental damage. When the instrument is activated, the stylus is caused to move around path 10 in the direction indicated by arrow 15. Thus, the stylus is first moved horizontally, away from the workpiece, from position 12 to position 18, and then it is moved vertically through position 14 to position 20, with shutter 16 in front of it. It has been moved to a position away from the opening 14. The stylus then moves generally horizontally towards the work piece to position 22 where it engages the surface of race 2. The stylus is then moved downward again while the tip remains in contact with the surface to be checked. During the downward movement, the output of the transducer associated with the stylus is detected so that the required measurements can be made. When the stylus reaches point 24, it is moved horizontally a short distance to the right, as seen in the drawing, to release the tip from the workpiece surface, and then back into position 12, thereby completing the cycle. Complete. The movement of the stylus between points 22 and 24 is done at a speed suitable for taking measurements, which is relatively slow. The movement between the other points, in particular between points 18 and 20 and points 24 and 12, is done at high speed to minimize the time it takes to complete the entire cycle. When the stylus is returned to position 12, shutter 16 is moved again to cover aperture 14.

If during movement between points 18 and 20, the stylus encounters an obstacle such as 26 or 26a, the instrument senses this and the stylus will move to the right as indicated by arrow 29 in the drawing. Horizontally, i.e., first moved away from the workpiece location, and then retracted into the housing of the instrument and positioned along a path 28 indicated by dashed lines as indicated by arrow 30. Returned to 12.

Referring to FIGS. 3-6, the stylus 8 is held by an inductive transducer 32, which is slidable in bearings 36 located at opposite ends of the tubular enclosure 38, of a vertically reciprocable rod 34. Mounted at the upper end, the tubular enclosure 38 contains the transducer 32 and its upper part 6 is fixed in the housing 40 illustrated in FIG. The vertical reciprocating movement of the rod 34, and thus of the transducer 32, is achieved by a lever 42, which is pivoted with respect to the housing 40 at its center 44, and at one end a hawk 46 engaged in a groove 48 in the transducer support structure 50. A dowel 52 is mated and at its opposite end engaged in a slot 54 of a cam 56 which is secured to a vertical spindle 58 driven by a constant speed motor 60. As the spindle 58 is rotated, the lever 42 oscillates from the position shown in FIG. 3 to the position shown in FIG. 4, moving the stylus from position 18 to position 20 and then from position 22 to position 12. To oscillate back to the position shown in FIG. The shape of the cam slot 54 is the fifth
Illustrated in the figure. When the dowel 52 is on the cam 54a,
The stylus is in position 12. The stylus 8 is rapidly moved from position 18 to position 20 as the cam 56 rotates so that the dowel 52 moves down the steep portion 54b of the slot 54. Portion 54c of slot 54 slopes gently upward so that the transducer moves slowly from position 22 to position 24 at constant speed as cam 56 rotates at constant speed. Thus, during this constant velocity movement, the stylus 8 crosses the surface under test. At a predetermined point shortly after starting this traversal, it responds to light passing through a slit (not shown) in a disc 63a (see in particular FIG. 3) which is fixed for rotation with the shaft 58. A signal for initiating data logging is generated by the optical sensing unit 61a (Fig. 6). When the transducer 32 reaches position 24, the dowel 52 enters the portion 54d, which is located after the transducer 32 is released from the workpiece surface.
Go up steeply to move quickly from 24 to position 12. As can be seen in FIG. 6, the optical sensing unit 61 is
When the stylus returns to position 12, ie, after one revolution of the spindle 58, the slit (not shown) formed in the disk 63 fixed to the spindle 58 is detected and the motor
Turn off 60.

The transducer 32 is held on the structure 50 by parallel linking arrangements that allow its generally horizontal movement, which causes the stylus to move from position 12 to position 18 and position 20.
To be transported to position 22. The parallel link arrangement includes a link 62 extending generally vertically and having its upper end pivotally connected to the transducer 32 and its lower end pivotally connected to the structure 50. A vertically extending leaf spring 64 having its lower end secured to the structure 50 and its upper end engaging the transducer 32 causes the transducer 32 to move to the left as seen in FIGS. 3 and 4. Energize. The spring force is adjustable by screws 66, and this arrangement keeps the transducer 32 in its leftmost position while the stylus 22 traverses the surface under test.

As the stylus moves from position 12 to position 18,
Movement of the transducer 32 to the right is accomplished by a cam 70, which is fixed to a spindle 58 and which is pivoted relative to the housing 40 at one end 72a and engages the cam 70 at the other end. Acts on the converter 32 via a lever 72 which holds 74 and a low friction protrusion 76 which engages the converter 32. Thus, when the spindle 58 is rotated by the motor 60 to start the upward movement of the rod 34, the cam
70 also rotates to move transducer 32 to the right. The movement of the stylus from position 12 to position 18 is shown horizontally in FIG. 2, but it is recognized that it includes an upward component in the mechanism illustrated in FIGS. 3-5. When the stylus reaches position 20, the surface portion 70a of the cam 70
Reaches the roller 74 and thus the transducer 32 can be moved to the left.

If the stylus 8 encounters an obstacle, such as 26 illustrated in FIG. 2, during the upward movement from position 18 to position 20, the transducer 32 is deflected to the right. This is aided by providing a chamfered surface 8a at the upper end of the stylus 8. Parallel link device 62 is configured to provide this movement. Thus moving to the right, the plate 79 held by the transducer 32 moves into the optical sensing unit 81 which produces a signal used to reverse the motor 60, so that the stylus is in its protective housing 40. It is pulled back immediately, thus minimizing the risk of damage from such obstacles.

As best seen in FIGS. 3, 7 and 8, the shutter 16 is fixed to one end of a spindle 80, which is surrounded by a twist ledge 82 which biases the shutter 16 to the position where the opening 14 is opened. To be done. The lower end of the spindle 80 carries a lever 84, which has a roller 86 thereon, which is engaged thereon by a cam 88 fixed to the spindle 58. The raised portion 88a of the cam 88 is positioned above it so that the spindle 58
When the transducer 32 is fully lowered and the stylus 8 is in a position to be retracted within the housing 40, the rollers 86
Engage with. As the spindle 58 rotates at the beginning of the measurement cycle, the portion 88a of the cam 88 moves away from the roller 86, causing the twisting rod 82 to move the shutter to its open position, which is indicated by the dashed lines in FIGS. 7 and 8. Let
In that position it engages the stop 90. The movement of the stylus 8 at position 24 without contact with the workpiece surface results in a low friction follower held by the transducer 32 which engages a normally stationary cam 94 best seen in FIGS. 6, 9 and 10. This is achieved by 92 (Fig. 6). Cam 94
As the follower 92 steps up, the transducer 32 is moved to the right so that the stylus 8 is no longer in contact with the workpiece surface and the stylus 8 is in position 24.
From position 12 to position 12, the cooperation between follower 92 and cam 94 includes a step 94a arranged to keep stylus 8 out of contact with the workpiece surface. The vertical location of position 24 is adjustable by rotating the cam 94 about its transverse axis, as can be seen in FIGS. 9 and 10. Once the position of the cam 94 is set depending on the workpiece to be measured, it remains in the set position for measuring all the same workpieces. However, if different sized workpieces are to be checked, the cam 94
The may be rotated to a new position to adjust the vertical location of position 24 so that the stylus is retracted from the workpiece surface after the required portion of the surface has been measured. This rightward movement of the transducer is detected by an optical detector 81a which detects the protruding portion 79a of the plate or blade 79.

To accommodate different workpieces and set the position of the cam 94 according to the workpieces to be checked, the instrument is provided with many different jigs or adapters, each designed for a particular workpiece. .
One such jig is shown at 100 in FIGS. 7, 10 and 11. Each jig 100 is formed with a hole 102 and a slot 104 for receiving a respective pin 106 fixed to the upper portion 6 of the housing 40 for accurately placing the jig in the required position, and a rotatable locking device 108 ( (Not shown in detail and not mentioned) are provided for fixing the jig to the upper part 6. Each jig is sized and shaped to accurately position a workpiece of a predetermined size with respect to the jig opening 112 that the stylus 8 will pass through when protruding from the housing 40. It has a carrying 110. The spring loaded lever 114 is provided to engage the work piece 2 with the barb 110 and hold it in place. Each jig has a downwardly projecting pin 116 for setting the rotational position of the cam 94 according to the dimensions of the workpiece to be supported by the jig. The pin 116 is secured within the jig 100 by threads (not shown) so that its vertical position can be adjusted when setting up the jig for a particular size of workpiece. As shown in FIG. 10, a pin 116 engages a plunger 118 which is slidable in a sleeve 119 carried by the upper part 6 and whose lower end is fixed to a shaft 122 on which a cam 94 is mounted. Engage the lever 120 that has been removed. As seen in FIG. 10, spring biasing means (not shown) are provided to bias the shaft 122 counterclockwise.

13 and 14 show the jig 130 used to calibrate the instrument. It is a fixture 100, except for the following:
Same as that of the invention, i.e. it does not include the barb 110 and lever 114 but instead is a precisely positioned recess 134.
A high precision ball 132, such as a high precision ball bearing, is provided and held in place by a leaf spring 136 secured within a block 138 above the jig 130. The jig 130 is provided with an element 140, which acts on a microswitch 142 placed on the underside of the top 6 of the housing 40 to set the instrument in the calibration mode when the jig 130 is mounted thereon. . Therefore, calibration will be easily accomplished as often as necessary.

Referring to FIG. 15, the main unit 500 includes a microprocessor 600, which is provided with an associated memory 602,
And the terminal device 502 and the printer 506 are connected to it by a cable 542. The interface board 604 includes a measurement button 536 and a print button 534, a calibration microswitch 142, and optical sensing units 81, 61a, 81a, 6
Responsive to the signals respectively generated by 1 to indicate an obstacle, start data logging, stop data logging and provide control signals to processor 600 to stop motor 60. The interface board 604, under the control of the microprocessor 600, has a digital display 5
Also signal 26 and 528.

Gauge board 606 receives the analog output signal from transducer 32 and converts it to digital form for application to microprocessor 600. The output of the converter 32 is
It is read at evenly spaced positions on the transducer 32 as it traverses the workpiece surface. This is accomplished by a position sensing arrangement that includes an optical grating 608 and an optical read head 610 that detects the position of the transducer 32 and one moves with the transducer 32 and the other is fixed. Lattice 608
Is illuminated by a light source 612.

When the terminal device 502 is connected to the computer 600,
The instrument is programmed to be controlled from the terminal device 502 and ignore any signal from the measure button 536 or print button 534. When the terminal device 502 is disconnected, the device will measure button 536 and print button 5
Controlled by 34, actuation of measurement button 536 causes processor 600 to perform a measurement cycle, where the transducer is moved around an infinite path illustrated in FIG. 2 and data from the transducer is logged. , And measurements are made on that data. This is an important aspect of the preferred embodiment of the present invention, because with the terminal 502 the tool can be set up by a skilled operator, and after set up, a relatively untrained operator simply jigs the workpiece. Place inside and measure button 536
The measurement can be performed on successive workpieces by driving the.

When the terminal device 502 is connected to the processor 600, various programs can be entered with the aid of the menu displayed on the display 540. An example of a preferred main menu is as follows.

1. Measurement / Calibration 2. Results 3. Setup 4. Input Parameters 5. Print Profile 6. Print Summary In order to set up the instrument for use with the same work piece in series, the stylus 8 makes contact with the work piece surface during the measurement cycle. First, a suitable jig 10 to define the location of position 24 to be moved without contact.
It is necessary to select 0 and secondly adjust the position of the pin 116. Thus, after selecting the jig, it is mounted on the fixture and then an example of a mass-produced workpiece (race 2) to be tested is mounted on the jig. Item 3 is selected from the main menu and is thereby entered into a program where coarse scale 620 and fine scale 622 are displayed on liquid crystal display 540 along with moveable pointers 624 and 626, which are coarse scale 620 and Each is associated with a fine scale 622 and visually displays the deflection of the stylus 22 in millimeters, which deflection is obtained by the processor 600 from the magnitude of the signal generated by the inductive transducer. The coarse scale 620 shows the deviation from zero in the positive and negative directions,
And includes a scale that represents 0.1 mm. The scale 622 of the spirit is 0.
Includes a scale that represents a 01 mm deflection. Manual drive button 628
(FIG. 15) is provided for processor 600 to turn the motor on or off, under the control of a skilled operator setting up the instrument. This button 628 is preferably located on the instrument such that it is not readily accessible to a relatively untrained operator performing tests on mass-produced workpieces. Using button 628 and noting the movement of pointers 624 and 626,
The transducer is set up by the operator to set up the instrument.
It can be made to move around the infinite path shown and the pointer allows the operator to move as the stylus crosses the workpiece surface containing the concave portion and as the transducer is moved away at position 24. The stylus deflection can be observed. Preferably, position 24 is located only a short distance below the end of the concave portion of race 2 and thus button 628 and scale 620.
And with the aid of 622, the position of the protrusion 116 is adjusted to provide the required location at position 24 only a short distance below the end of the concave surface. Thus, the stall datalog signal is generated by unit 81a without unnecessary delay so that processor 600 begins performing the required calculations on the collected data without any unnecessary delay,
These calculations begin in response to the signal from unit 81a. The speed of movement of the instrument may be increased.

It is also necessary to enter certain parameters before using the instrument. This is accomplished by selecting item 4 from the main menu and in response the input parameter table is displayed. A preferred example of this is as follows.

1. Unit (Metric / Imperial) 2. Percentage ignored (0 ... 30) 3. Stylus tip radius (5 to 99 microns) 4. Print format (Profile / Summary) Using this table, the operator should make a measurement First, insert the unit. Next, the operator enters the so-called "ignore length" (IGNORE LENGTH). This can be seen from Figure 19, which shows length neglect at the beginning and end of the concave profile being measured. Thus, up to 30% of the profile length may be ignored in the calculations performed. The particular number selected depends on the workpiece to be checked. FIG. 19 also shows position 24
And the path of the remote stylus tip leaving the workpiece surface is shown by the dashed line.

Then the radius of the stylus tip is entered and then whether the required print format, i.e. the trace of the profile, is required, or whether a simple numerical print of the radius and peak-to-low point measurement (PV) is required. Can be put in.

After the instrument is set up as described above, it needs to be calibrated before it can be used. The calibration is actually
Even if the set-up cannot be changed, it should be done regularly, for example once a day. To calibrate the instrument, a calibration jig (FIG. 14) with calibration balls is attached to the instrument. The calibration may then be performed by selecting item 1 from the main menu (if the terminal is connected) or by simply pressing the measure button 536. FIG. 18 illustrates the portion of the ball surface that is traversed during calibration and the path of the stylus tip after leaving the ball surface is shown in dashed lines. The instrument is pre-programmed with the radius and configuration of the calibration ball 132, and thus from this, and from the data obtained in the calibration cycle, the instrument makes the necessary calculations to perform the calibration. These may be done in well-known fashion and thus require no further explanation.

Item 2 from the main menu allows for the display of past results stored in the instrument, and items 5 and 6 are for printing a profile or a summary no matter which input parameter 4 is selected. Give orders.

When the terminal is connected and a measurement is made, the results are displayed on the display 540 in the configuration shown in Figure 17, where the horizontal straight line 630 represents the radius of the surface and the trace 632 represents the morphological error. , And the radius and PV measurements are displayed at the top of the illustrated display. Furthermore, whether or not the terminal device 502 is connected,
The radius is displayed on display 526 and the PV is displayed on display 528.

From the above description, it is understood that once the instrument has been set up and calibrated, it may be used to check the same workpiece in succession with efficiencies not previously achieved. In particular, relatively unskilled operators simply have to place each workpiece in the jig and actuate the measurement button. The actuation of the measuring button causes the start of the measuring cycle, which causes a sudden protrusion at the beginning, a speed change to a speed suitable for data logging, a crossing of the workpiece for the purpose of data logging, its movement in the computer. Including a stylus movement about its infinite path with the computation program initiating, rising away from the workpiece surface and subsequent abrupt retraction to its rest point in the protective housing. Following the calculations performed on the logged data, the computer has two digital displays 526
Radius and PV values are displayed on and 528 from which the operator can know if the workpiece is acceptable. The preferred routine that the computer should follow in the measurement cycle is as follows.

1. Datalog 2. Filter data 3. Detect edges of curved surface to determine profile length 4. Calculate calibration constant if calibrated 5. Calculate arc compensation 6. 80% of profile length Utilize to calculate radius 7. Subtract radius from obtained result 8. Calculate peak-low point taking into account length ignoring 9. Show result This is all a few workpieces per minute Will be done in a cycle that only takes a few seconds so that can be checked. In a preferred embodiment of the present invention applied to race measurement, a throughput of 4 workpieces per minute can be achieved.

It will be appreciated from the above description that the device will be in different states at different times. Preferably, the status of the instrument at any given time is indicated by the numeric code displayed on digital display 526. And preferably, the code is shown on the display plate 530. An example of suitable code is:

1. Ready state. In this state, the instrument is in standby mode.

2. Measurement status. The fixture is in this state when the fixture 100 is provided and a measurement cycle is being performed in response to a measurement button or command from the terminal.

3. Calibration. This is 2, but the calibration jig is in place in the instrument.

4. Print. This is self-evident.

5. The terminal is in use. This is self-evident.

6. Error. The specific error that occurs is preferably indicated by an additional digit as follows: 001 Not calibrated 002 Manual switch 628 In use 003 Obstacle 004 Out-of-state 005 Profile edge not detected 006 The printer is not ready.

Providing this status code indication on the top of the machine adjacent to the digital display enhances the efficiency of the machine and its suitability for use by relatively untrained operators.

FIG. 20 illustrates a modified version of the jig that may be adjusted to race different sizes. In FIG. 20, element 110 has slot 704 within element 110.
Threaded shank (not shown) passing through
It can be adjusted in the direction of the arrow 700 by loosening the knob 702 having. Further, the lever 114 is mounted on the block 706, which is slidable in the direction of arrow 708 and can be clamped in a selected position by means not shown. Thus, plate 110 and block 706
By adjusting the position of, different sized races can be adapted and accurately positioned with respect to the infinite path that the stylus 8 follows during the measurement cycle. Many modifications may be made within the scope of the invention. For example, if the tool is to be used with only one particular type of workpiece, then a replaceable jig need not be provided, and the tool simply follows one predetermined path with the stylus. Can be arranged as is possible. It is highly preferred that the retracted position of the stylus should be below the fixture or support on which the work piece is mounted, but instead the transducer and associated features and protective housing should allow the work piece to be mounted during testing. It can be positioned so that it can be positioned on one side of the place where the stylus protrusion and retraction movement can be horizontal rather than vertical. As a further alternative, the mechanism and protective housing may be provided above the workpiece location. However, the arrangement shown in the drawings, in which the workpiece is positioned above the protective housing and the surface of the workpiece under test extends away from the protective housing, is the positioning of the workpiece on the instrument and its removal from the instrument after testing. It is generally considered to give the removal the greatest convenience and efficiency. The illustrated cam arrangement, with many cams mounted on a single spindle driven by a single motor, provides an advantageous mechanism for providing the primary movement of the stylus and is thus efficient. It will be appreciated that a rugged and relatively low cost instrument can be provided. Since the cams provide the timing of the various movements and they may be fixed with respect to each other and in fact directly together, the synchronization of the movements caused by the cams cannot be lost.
Reception of signals from the transducer and initiation of processing can be accomplished in a variety of different ways, such as by sensing the edges of the concave portion 4 of the workpiece, by sensing the contact between the stylus and the workpiece. This may be done by sensing 58 specific angular positions, or in any other suitable manner. Since the stylus is retracted within the housing between measuring operations, the risk of damage to the stylus or transducer is substantially eliminated. Since the instrument is set up so that the transducer follows this path to measure each of the same workpieces in succession, and the movement of the transducer is high when ejected and retracted, and The measurement can be completed with maximum efficiency and without interrupting the production flow because of the relatively low velocity suitable for measurement when in contact. Furthermore, if the device should be used with many different workpieces, the replaceable jig provides a simple and efficient means for reconfiguring the instrument to handle such alternative workpieces. .

Although the instrument has been described with reference to the drawings under the assumption that the radius and morphology should be measured, it provides an instrument according to the invention suitable for making other measurements such as surface texture. It is also possible.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of an instrument according to a preferred embodiment of the present invention. FIG. 2 is a drawing illustrating the principle of operation of the preferred embodiment of the present invention. FIG. 3 is a cross-section through a portion of the preferred embodiment of the present invention. FIG. 4 is a cross-section similar to FIG. 3 but showing the device in a different state. FIG. 5 is an exploded view of the cam track included in the instrument of FIGS. 3 and 4. FIG. 6 is a schematic sectional view taken along the line VI-VI shown in FIG. FIG. 7 is a plan view of the device shown in FIG. FIG. 8 is a drawing illustrating the operation of a part of the instrument shown in FIG. 7. FIG. 9 is a schematic partial sectional view taken along the line IX-IX in FIG. FIG. 10 is a schematic partial cross-sectional view of the portion of the instrument shown in FIG. 9 but viewed in the opposite direction. FIG. 11 is a plan view of a removable jig provided with a device. FIG. 12 is a partially cut-away side view showing the jig of FIG. 11 mounted on an instrument. FIG. 13 is a plan view of an alternative jig for use in calibrating the instrument. FIG. 14 is a partially cutaway side view showing the jig of FIG. 13 in place on the instrument. FIG. 15 is a block diagram of an electronic circuit included in the preferred embodiment of the present invention. FIG. 16 shows a display made on the display device included in the preferred embodiment. FIG. 17 shows another form of display that can be made. FIG. 18 is a drawing to help understand the calibration operation performed in the instrument of the above figures. FIG. 19 is a drawing to help understand the performance of the measurement operation in the preferred embodiment. FIG. 20 is a schematic perspective view of an alternative form of jig that may be used in the preferred embodiment. In the figure, 2 is a race, 8 is a stylus, 10 and 28 are paths, 32 is a transducer, 40 and 506 are housings, 500 is a main unit, 508 is a workpiece support structure, and 600 is a microprocessor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Alan Gerald Merrills El E10 1A / F, UK, Hinckley Mount Road, 6

Claims (30)

(57) [Claims] 1. A metrology tool (500) for measuring the surface of a workpiece (2), comprising a protective housing (506) and placing the workpiece in a predetermined position relative to said housing. Positioning means for workpieces (508)
A surface sensor (8) arranged in the housing, and a driving means (60, 58, 42, 34) arranged so that the surface sensor follows a predetermined path (10), At the surface sensor protrudes from the housing, traverses the surface to perform a measurement operation, and is then retracted into the housing (506), the drive means (60, 58, 42, 34) being connected to the path ( 10) is arranged to include a loop, the surface sensor (8) being across the workpiece surface when moving in one direction in the loop and spaced from the workpiece surface when moving in the opposite direction in the loop. And the drive means (60, 58, 42, 34) move at a relatively slow speed in the one direction when the surface sensor (8) crosses the workpiece surface, If the scan surface spaced further arranged to move at a relatively high speed in the opposite direction, the instrument. 2. The device of claim 1 wherein said one direction is generally perpendicular to said housing (506). 3. An instrument according to any one of claims 1 to 2 wherein the drive means is operable to project the surface sensor at a relatively fast rate. 4. An instrument as claimed in any one of claims 1 to 3 in which the drive means is operable to retract the surface sensor into the housing at a relatively fast rate. 5. A surface sensor (8) according to any one of claims 1 to 4, wherein the surface sensor (8) is moved away from the position of the workpiece surface before the retracting operation is started. Equipment. 6. The instrument of claim 5 wherein the instrument includes means (94) for adjusting the point at which the surface sensor separates from the workpiece surface after a measurement operation. 7. The drive means (50, 58, 42, 34) is moved in a direction away from the position of the workpiece surface to be measured by the surface sensor before or during the projecting movement, so that the projecting movement is performed. 7. Any one of claims 1 to 6 which is then operable to move the surface sensor (8) such that the surface sensor moves towards the position of the workpiece surface to be measured. The device described in Crab. 8. The drive means drives first and second cams (56, 70) rotatable with respect to a common shaft and fixed to each other, and the first and second cams. 8. A motor according to any one of claims 1 to 7, comprising a single motor (60) for the purpose of connecting the first and second cams to the surface sensor (42, 34). Equipment. 9. A shutter (16) for opening and closing an opening in the housing in which the surface sensor (8) moves, and for moving the shutter to a closed position when the surface sensor is retracted into the housing. And when the surface sensor projects from the housing, means for moving the shutter to the open position (58, 80, 82, 84,
86, 88) and the device according to any one of claims 1 to 8. 10. The shutter is operable by a further cam (88) which is coaxial with and fixed to the first and second cams and is driven by the single motor. The device according to item 8 or 9. 11. An instrument according to any one of claims 1 to 10 wherein the surface sensor (8) is a stylus used to contact the surface of a workpiece. 12. The workpiece positioning means (508).
Is detachably fixed to the housing (506) and is arranged to place a workpiece (2) of a predetermined size and shape at a position where the measuring operation is performed by the surface sensor. An instrument according to any one of claims 1 to 11 including a piece support device (100). 13. The tool comprises a plurality of said workpiece support devices (100) adapted for respective workpieces of different sizes and / or shapes and exchangeable with respect to each other. Apparatus according to clause 12. 14. The workpiece positioning means (508).
Is a workpiece support device (10) that is adjustable to receive workpieces of different sizes and / or shapes.
A device according to any one of claims 1 to 11 including 0). 15. The workpiece support apparatus contains a workpiece such that all of its surfaces to be measured are in substantially the same position.
The device according to item. 16. The workpiece support device (100) comprises:
Device according to any of claims 12 to 15 when dependent on claim 6, arranged to perform the adjustment of claim 6 when mounted on the device. . 17. An instrument according to any of claims 1 to 16 wherein the workpiece positioning means is located on top of the housing. 18. A combination comprising a jig (130) for calibrating an instrument, wherein the jig is attachable to and detachable from the instrument and is arranged to be sensed by the surface sensor. A device according to any one of claims 1 to 17, further comprising an element (132), said instrument comprising means (142) for sensing the mounting of said jig to provide a signal for initiating a calibration operation. The device according to any one of paragraphs. 19. The obstacle sensing means (79,) wherein the instrument is operable to immediately retract the surface sensor into the housing in response to the surface sensor engaging an obstacle during a projecting motion. Claim 1 including 81)
Item 18. The device according to any one of items 18 to 18. 20. The device of claim 19 wherein the surface sensor has a chamfered end that causes deflection upon impact with an obstacle. 21. An apparatus according to claim 19 or 20, wherein the obstacle sensing means is operable to sense movement of the surface sensor in a direction away from the workpiece surface. 22. A single manually operable control member (536) wherein the instrument starts the measurement cycle when driven and is repeatedly driven to repeat the measurement cycle.
An instrument according to any one of claims 1 to 21, including: 23. The instrument includes computer means (600) for performing a measurement operation on the workpiece using the surface sensor and terminal means (502) for inputting data to the computer means. , The control member (5
An instrument according to claim 22, wherein 36) is independent of said terminal means and is drivable for instructing said computer means to perform said measuring operation. 24. The computer means is arranged for the terminal means to receive instructions for performing the measuring operation.
The device according to claim 23. 25. The terminal means is removable and separable from the instrument.
The device according to paragraph 23. 26. The computer means is programmed for performing a set-up operation using the terminal means, the set-up operation defining a measurement cycle which can then be repeated by actuation of the control member.
The device according to claim 23 or 24. 27. A first partition (52) in the housing.
4), electrical means that are placed in the first partition and generate heat in operation, a second partition (512) in the housing, and the second partition and that are subject to temperature changes. Atmospheric air is drawn into the second partition so as to at least limit temperature changes in the sensitive measuring means (510) and the measuring means due to heat from the first partition, and the atmosphere is above the measuring means. A device as claimed in any one of claims 1 to 26, including a means (520) for causing the second partition to exit. 28. A method for producing a large number of identical workpieces (2), including a method of manufacturing workpieces by mass production, said method comprising successively measuring the same surface of said workpieces with the same metrology. Providing the metrology tool in a state suitable for performing an operation, and performing the same metrology operation on at least a majority of the manufactured product using the metrology tool, the metrology tool comprising: A metrology tool for measuring the surface of a piece, comprising: a protective housing, a workpiece positioning means for placing the workpiece at a predetermined position relative to the housing, and a workpiece positioning means arranged in the housing. A surface sensor and drive means arranged such that the surface sensor follows a predetermined path, wherein The surface sensor projects from the housing, traverses the surface to perform a measurement operation, and is then retracted into the housing, the drive means being arranged such that the path comprises a loop, and the surface sensor is When moving in one direction in the loop, it traverses the workpiece surface, when moving in the opposite direction in the loop, it is spaced from the workpiece surface, and the drive means is when the surface sensor traverses the workpiece surface. Is further arranged to move at a relatively slow speed in said one direction and at a relatively fast speed in said opposite direction when spaced from said workpiece surface. 29. The method of claim 28, wherein the metrology operation is performed in a workshop in which the workpiece was manufactured. 30. The instrument logs data from the workpiece and processes the data to provide metrology information, and the instrument is further operable to output the metrology information. , Processing and output are all done in the workshop,
A method according to claim 29.